


Unleashed

by OverexcitedDragon



Series: Sebaciel's Kinkmas in July 2020 [5]
Category: Kuroshitsuji | Black Butler
Genre: Bestiality, Extremely Dubious Consent, Knotting, Other, Shapeshifting, Shotacon, i had to look up canine reproduction for this, yall better be thankful for my sacrifices
Language: English
Status: Completed
Published: 2020-07-20
Updated: 2020-07-20
Packaged: 2021-03-04 20:54:02
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 3,552
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25402657
Author URL: https://archiveofourown.org/users/OverexcitedDragon/pseuds/OverexcitedDragon
Summary: Ciel thinks there's power in abusing Sebastian's shapeshifting abilities, he thinks there's catharsis in looking down on his childhood dog and tugging violently at its leash like he never could as a young child.Ciel is unfortunately quite wrong.(Prompt XIX: FREE DAY - Bestiality)
Relationships: Sebastian Michaelis/Ciel Phantomhive
Series: Sebaciel's Kinkmas in July 2020 [5]
Series URL: https://archiveofourown.org/series/1813207
Comments: 16
Kudos: 240
Collections: Kuroshitsuji





	Unleashed

**Author's Note:**

> Thank you @notsafeforworse for beta reading yet again late at night ily baby

“Bigger snoot-- not like _that,_ I meant _longer!_ ” Ciel chastised. “And don’t forget the longer hair… no, _not that long_ …”

It was a silly game, really, but in Ciel’s defense, it was entirely Sebastian’s fault.

The demon had let out the week before that he could _shape shift._ Ciel immediately wanted to know: how far? How big or small could he get? Only real living beings, or mythical creatures as well? A dog? A bird? A whale?

Ciel knew Sebastian had regretted telling him when his numerous requests started earning biting remarks before the bedruging transformations finally came. But it was a thrilling new world, and the boy was easily bored and much too excited by new things. And, again, it was entirely Sebastian’s fault for even letting it out.

Not to mention, he owned the demon. He could very well do whatever he wanted with the creature. He could be spending his time whipping the butler’s back for fun, so he should really be grateful all Ciel wanted was some harmless magic show.

But the drawback was Sebastian’s… mood. Ciel’s curiosity towards the limits of the demon’s shape shifting abilities replaced another pastime that the butler was much too fond of. But could Ciel be really blamed for it? It was much more interesting to watch a demon turn into a hundred different animals, than have it fuck Ciel every night to stave off boredom and nightmares.

So Sebastian could suck it up, really. It wasn’t his choice in any regard, and the brooding, clicking his tongue, showing off fangs, or letting his hand wander while dressing Ciel would do nothing to gain back the boy’s favors.

If anything, it was fun to torture the butler.

It had been a week since Sebastian last fucked him, and Ciel was most amused by the demon’s displeasure.

Today, though, his request was quite the specific one, and Sebastian seemed incredibly irritated while Ciel carefully molded him into his namesake while showing him the only remaining photo of the deceased dog.

Sebastian couldn’t speak, apparently, while in his animalistic form, which Ciel was most delighted by, because it meant he would hear no biting remarks or teasing words while he all but played with the demon as if it was made of clay.

“He was bigger, too, you’re much too small--” Ciel started, then frowned in deep thought. “Although maybe I simply grew.”

The dog shook its head profusely.

“I suppose you would know better…” He muttered in annoyance. The demon’s inability to lie wasn’t always handy. “I think his tail was fluffier, too. This is too thin.”

After a few minutes of tweaking the creature’s appearance, Ciel was certain he had recreated his late dog perfectly.

When Ciel finally took a step back to look at his work, his breath hitched. It was truly uncanny, this familiar massive animal, jet black and regal looking, staring him down with blood red eyes. His whole body seized up to protect him from the nips and pokes that never came, and it took long enough for him to finally feel comfortable stepping towards the dog.

Ciel knew it was still Sebastian when he gently stroked its head, he knew it was still the demon when he scratched behind its ear and squeezed its neck in a choking hug… it wasn’t affection, it was power. Finally being able to pet the damn mutt made him feel like a proper owner, not a victim of the animal’s sudden aggression. Sebastian cocked its head in a silent question, but Ciel didn’t grace it with a response.

Dogs don’t need to know the whims of their owners.

“Lie down.” Ciel said, testing out his limits with the demon.

Sebastian didn’t budge. The boy frowned.

“Lie down, _that’s an order._ ”

The dog laid on the floor with a huff, crossing its front paws.

“Stay.” Ciel ordered, and then walked to his father’s desk a handful of steps away, fumbling around the drawers. When he finally found the collar and leash, he couldn’t help but smile, and it almost felt genuine.

He turned around to head back, but the massive creature was right behind him.

“Sebastian! I told you to stay!”

Sebastian barked.

Ciel pouted. Commanding the dog every time would be a pain, but he supposed the demon wouldn’t listen to him otherwise, not with how irritated it was already.

“Sit and stay still, that’s an order.”

The dog obeyed, and Ciel worked the collar around the creature’s neck. It was difficult, and he fumbled with the buckle an embarrassingly long time, earning a foul yawn from the dog as what he assumed was a tease.

“It’s difficult, leave me alone…” He mumbled.

When the collar was safely attached, he struggled less with the leash. Soon, Ciel had his dog collared, leashed, and obedient at his hand. And it felt fantastic.

He tried walking the bloody thing, but was tugged back by the taut leash of the dog who was surely still _staying still_ , as it was ordered. Ciel fell back on his bottom, and looked back at the creature, and those ruby eyes seemed much too smug for his taste.

“You only want to act as a dog when it benefits you, I see…” Ciel grinned. “Fine. Sebastian, be a dog until I take this collar off you, that’s an _order_.”

Ciel thought that was a smart idea.

If only he had known at the time how wrong he was.

Sebastian’s demeanor immediately changed, and it was absolutely terrifying. The dog changed its stance and posed like he was about to pounce Ciel, tail wagging and tongue out before it barked happily at the boy.

“That’s disgusting, stop th--”

He was immediately interrupted by the dog’s foul licking, and as the creature was massive and surely still as strong as Sebastian was in his human form, Ciel didn’t get the chance to stand up.

“ _Stop that!_ ”

The bark made his ears ring, much too close and much too loud, but at the very least Sebastian had stopped _licking_ him like an excited puppy.

Then it started _sniffing_ him.

“Sebastian, by the _Heavens_ \--”

Its cold nose poked at Ciel’s cheeks, his neck, over his chest, and when the creature attempted to sniff his _crotch_ of all places, Ciel smacked its face.

Usually, that worked with Sebastian, the dog. He would stop molesting Ciel’s pants like a rutting mutt.

But this was Sebastian, the demon. A demon who hadn’t gotten his fair share of Ciel’s body for over a week. And when Sebastian, the massive black dog who had harassed Ciel for years of his life, much too big to be pushed away when mommy and daddy weren’t there to help, started growling rather than yelping at the only remaining defense Ciel had, the boy felt his heart sink.

He knew all he needed to do was order him to stop, but Ciel’s voice was caught in his throat, his whole body frozen, and all he could do was watch. Watch the dog sniffing his crotch aggressively, pushing its long nose against Ciel’s sensitive flesh, huffing and growling like a rabid animal.

Its jaw snapped once, and Ciel squeaked. Then it snapped again, but this time the sharp teeth closed over Ciel’s pant legs. And then it pulled.

Ciel felt his eyes prickle.

“S-Sebastian, stop, this isn’t funny…” It was almost a sob.

His shaky hands pulled at his trousers, trying desperately to keep them in place, but Sebastian’s renewed growling made his body freeze, and Ciel all but cried while watching the dog pulling his shorts down, thrashing its head around like it was playing tug of war with Ciel’s pride, exposing the boy’s flesh while tangling his feet all at once.

“Sebas...tian…”

Ciel tried. Tried to bring out the words, to order the damn demon to _stop, please, stop_ , but his voice was a mere squeak, his legs shook, and he was nothing but a helpless little boy whose parents left with his brother on a trip and there was no staff nearby to help him, to save him.

So why in the bloody heavens did he have an erection?

The boy tried to push Sebastian’s head away when its wet, cold nose sniffed at his crotch once again, but this time there was no cloth to stop it from pressing hard against his sensitive flesh. It made Ciel whimper in something odd and humiliating, and his hands were small and useless against the enormous dog.

And then it _licked_ him, and Ciel couldn’t stop it, couldn’t stifle it, couldn’t swallow down the humiliating moan that broke out of his trembling lips.

“No, _no, no,_ Sebasti-- _ahhnn_ …”

The dog started licking Ciel’s twitching prick copiously, and by the gods it was _soft,_ like nothing else Ciel had ever felt. The long, pink, wet tongue licked at him like the bloody dog was parched.

Before Ciel could properly even understand what was happening, his body shook _hard_ , and the orgasm hit him like a bullet. There was a loud whine before his cock dribbled the scant release over his own clothes.

“You… filthy… dog…” Ciel gritted out, sprawled on the floor and heaving like he had just run a marathon. “I hate you… you’re disgusting…”

But when he finally leaned his head forward to look at the dog, Ciel realized his problems weren’t quite over yet.

There was a look Sebastian always gave Ciel which he absolutely hated. The demon would squint, and there would be a glint of mischief in those ruby eyes, and it always meant trouble for Ciel-- some humiliating teasing, some sudden schedule change, a family visit that was being kept from Ciel for days and was to be prepared for within the hour.

And, recently, it would mean Sebastian wasn’t done with Ciel’s body. No matter how many rounds he had had to endure beforehand.

That same look was plastered all over the cursed dog’s face.

Ciel’s mind worked fast. After licking his prick until Ciel came, the next step was quite obvious. And in this shape…?

The boy immediately turned around to crawl away, desperately attempting to kick off the trousers tangled around his feet, but Ciel realized his mistake the second he heard heavy breathing beside his ear.

Ciel froze, and slowly looked to his right, where sharp fangs met him in what looked like an obscene grin.

“Seb...astian…?” He whimpered.

Something hard and heavy pressed against his rump, and Ciel’s head snapped back.

Of course, _of course._

The damn dog’s prick, red and slick and _definitely_ much, _much_ bigger than dogs were supposed to be, was vulgarly laid in between his cheeks.

“Don’t, _don’t!_ ” Ciel tried.

And there was a pause.

And Ciel knew exactly _why._

Sebastian was waiting, its breath heavy and warm against Ciel’s ear, tongue out like an excited puppy, because the bloody demon knew-- he _knew_ that if he waited, if he allowed Ciel enough time to order Sebastian to _stop_ , if Ciel still didn’t issue the command, it would mean one thing only.

It would mean Ciel _wanted it._

And there _was_ a hint of curiosity in the back of his mind, a thought Ciel didn’t want to allow forming.

A dog. _Sebastian_. The creature that made his childhood a special flavor of hell. And all those times it would lay down on its back with its red glossy prick out shamelessly, asking for belly rubs like some perverted wild animal. And how endlessly curious Ciel had been growing up, watching it hump the disgruntled maids and lick its own shame out in the open, right in front of him. Right before licking Ciel’s face with the same tongue.

As much as there was fear, there was curiosity as well.

This was a different kind of immoral. Allowing Sebastian to fuck him as a human was wrong, yes, but he could still call himself a victim, could still blame the demon for its actions, as the human mind is complex, and understands morality. But this? A _dog?_ Dogs are easily pushed away, easily ordered, easily beaten, and they’re much more idiotic than mere children. So many ways to stop it, and yet… Ciel didn’t want to.

And Sebastian, the wretched creature, he knew it. Knew Ciel _wanted it._

The boy was rewarded with a long lick across his cheek. He felt the warm animal shifting above him, and then the wet, burning hot cock rubbed against his hole. Ciel’s whole body shook, his hands moved to uselessly hold the long front legs on each side of his head, and he closed his eyes.

The thing had a pointed tip, like it was made to invade whatever hole it saw fit, and Sebastian wasted no time thrusting its furry hips forward, shoving its wet cock inside Ciel, making the boy whine loud and desperate. Ciel was half thankful he was partially used to this sort of intrusion, but the week of celibacy made it hard to take it all in easily. He tried to breathe in deep, head hanging heavy between his shoulders.

And then Ciel felt the thing swelling inside him, thick and bulbous and stretching him as much as Sebastian’s human cock would. The dog’s front paws moved to hug Ciel’s hips, and his chest and head collapsed to the floor, arms too weak to properly hold him up.

When Sebastian moved, all Ciel could do was shake and whimper, he felt the dog hair pressing soft against his rump, and felt the thick cock shoving into him, filling his insides to the brim. There was something about the situation itself that made it all the more shamelessly pleasurable, this massive dog of his childhood fucking Ciel like a common bitch, heavy and hot against his back, heaving and drooling over his neck, shoving its filthy prick deep inside him over and over.

Sebastian growled and barked over him, and Ciel almost replied with a bark of his own-- if he was to be fucked as a bitch, nothing stopped him from _acting_ like one. There was a suspension of morality, of proper _thought_ that just drove him absolutely insane. Ciel’s brain was scrambled with every thrust of the dog’s hips, and all he could do was drool and heave and whine just as the mutt did.

Then the dog barked again, and the bitch barked back.

Before long Ciel felt it-- and he knew it was coming, really, was mentally preparing himself for it the whole time, grinning like a crazed man and waiting, hoping, _whining_ for it to come soon, _sooner_. The thick, fat knot at the base of Sebastian’s cock finally pressed hard against his abused hole, and it hurt like absolute _hell_ , stretching him open and pushing the dog’s prick even deeper inside. Ciel’s head was foggy, his body useless and hips barely held up by his shaking knees. When Sebastian’s knot finally slipped inside, massive and unforgiving, Ciel felt like his stomach churn in nausea, in pain. It was hard to breathe, and his heartbeat drummed loudly in his ear.

And then Sebastian came, slowly filling him with filthy, repulsive dog spunk. Ciel hiccuped, and it sounded too much like a giggle. He was collapsed, held up by the dog’s knot plugging him tight while he obediently took every drop of Sebastian’s cum. Ciel saw the dog’s muzzle come into his blurred view, and felt a soft, wet lick against his open lips. The boy opened his mouth further, welcoming the revolting tongue, lapping against it with his own obscenely, though his mind was much too gone to really care.

After Sebastian seemed satisfied with the dripping mess he made of Ciel’s face and mouth, the dog swung a leg over the boy’s back to turn around, and the chill of the room finally hit Ciel’s sweat glistening skin when there was no animal fur to cover him.

He almost fell asleep while waiting, feeling his stomach filling slowly with more and more spunk, warm and heavy while Sebastian only stood there, huffing with its tongue out, holding Ciel’s hips up by nothing but its swollen knot.

Ciel noticed the leash end lying uselessly beside him, and couldn’t help but chuckle.

 _Owner_ his arse.

 _Power_ … what a joke.

When it was finally over, after what felt like an eternity, the knot inside Ciel disengorged and the dog slowly pulled its filthy prick out. A torrent of cum spilled from his loose hole, staining Ciel’s thighs and most certainly the study carpet. It felt odd being suddenly so _empty_ , though there was most definitely still plenty of seed coating his insides even when so much of it dripped out.

Ciel’s hips collapsed to the side with nothing to hold them up, and the boy nearly did fall asleep this time, exhausted in every sense of the word, until he felt a wet cold nose poking and nuzzling his face. Ciel groaned, but understood the dog’s wants; it was his own orders that it was to act as an animal until the collar was out, after all. So his shaky fingers reached up to the neck of the creature, and with so much effort Ciel thought he was about to cry and give up, he finally, _finally_ pulled the damn collar off.

He only blinked once, and when Ciel’s eyes opened once more, what stood in front of him were pristine formal shoes and long, black clad legs.

“Did the young Master have fun owning a proper dog, did he?” Sebastian teased, but there was an edge of annoyance in his voice, like he still hadn’t forgiven Ciel for withholding his body for so long.

Even in this state, Ciel still hadn’t repent, apparently.

“Clean me up,” Ciel managed to groan out. “And rid me of these ruined trousers, you filthy mutt…”

“Oh, my dear little Lord,” The demon cooed, picking up Ciel in a gentle bridal carry that made it all the more humiliating. “You see, I was simply following your orders.”

“Dogs don’t fuck their Masters…”

“That is because Masters usually push humping dogs away.”

Ciel was quiet for a long moment as Sebastian walked down the corridor towards the bathroom.

“It wasn’t all bad.” He mumbled.

“Oh?”

“I like having you on a leash. It suits you.”

“Does it, now?” Sebastian’s smile was abnormally sharp. “Because you took very little advantage of holding that leash, Master.”

“I was busy.”

“Busy getting fucked by your dog and _enjoying_ it.”

There was a beat. Ciel was much too tired to chastise, to fight back. His head lolled over to Sebastian’s chest.

“Dogs are servants just as much as staff.”

“I take it nobles fuck their staff just as well?”

Ciel chuckled. “You must think this is some sort of jab, but it is much more common that you would realize.”

The butler hummed. “And what about animals?”

“Also quite common. More than you’d think.”

Ciel wasn’t lying, but it wasn’t the whole truth either. Immoral and reprehensible things happened all the time, especially in a country as broken as England, they were simply all done in secrecy. Most of the time. Farmers fucked their goats, housewives bent over for their dogs, aristocrats used their maids like objects. Humanity was filthy through and through, and Ciel wasn’t safe from that filth. He was both victim and perpetrator of it.

The demon set Ciel down on his feet, and the boy wrapped his arms around the broad shoulders to hold himself up while he was properly undressed. He was used to this, to shaky legs and a leaking hole after Sebastian had had his way with him.

“I take it my young Master appreciated owning a proper dog, then?”

Ciel thought for a long moment. There was a lot to lose in whatever response he gave the butler, so he simply said the first thing his mind provided.

“Like I said, I enjoyed having you on a leash.”

“I see.”

“And I can’t say your pathetic animal instincts weren’t entertaining as well.”

“ _I see._ ” The demon grinned, sharp and dangerous.

And it _was_ dangerous. _This._ This relationship, this dynamic. Allowing his demon to take the reigns of it all, to have his way. Maybe Ciel should whip him, other aristocrats did too, both staff and dogs; or maybe Ciel should keep him leashed, maybe he should just keep his distance…

It was a laughable idea. _Keep his distance._ After all of this? After being molested nightly by the demon, after being used like bitch in heat by it?

No, there was no going back from any of this.

“Has the young Master finished withholding my meals? Or maybe I should turn into a _horse_ next?” The demon snarled.

Ciel looked down at the man kneeling before him, the man holding his weight after having made his legs useless himself, peeling layers of cloth until Ciel was bare, the man who reached into his chest every night to clutch his heart with sharp claws, who marked and used his body as he saw fit.

And Ciel chuckled.

“Fine. Have it your way.” He conceded. As he always did.

Because when a lamb held the wolf’s leash, all it did was become its only victim.


End file.
